Most of the elements in Receiving Chokutotsu apply here:
- The tiny step and receiving of the strike
- The correct distance
- Posture while receiving
For dattotsu the motodachi has two extra tricky bits to focus on as well as all of those points.
Firstly the motodachi wants the strike to be straight. The striker doesn’t drop under the motodachis mokuju. Dattotsu can be considered the “evading” strike. The striker is “evading” the sideways pressure created by the motodachi. To aid the striker in not dropping their kensen down to get a clear strike the motodachi can raise their mokuju slightly when the strike has commenced. You can see this at 00:42 the motodachi created the sideways pressure and the strike starts sliding in straight along the barrel. After a couple of centimetres Terada sensei lifts the motodachis kensen a small amount to enable the striking mokuju an easy and straight path to the target. At 01:25 you can see that the strikers mokuju dips down a couple of inches under the mokuju during the strike (and Terada sensei kindly reminds me what we are trying to do here). At 01:28 you can see the striking kensen maintain contact almost the whole way to the target.
The second important difference to chokutotsu is that the motodachi has his mokuju on the wrong side after the strike is complete. During the second step moving backwards the motodachi must return to the correct side. At 01:46 you can see that the motodachi almost maintains contact between the two mokuju during his two steps back. Try to avoid too much clacking noises during this movement, relaxed hands will make things smoother. When learning this extra movement it is easy for the motodachi to make a mistake in the distance as seen at 01:54. When this happens as motodachi encourage the striker not to “reach” for the target. Instead simply do a correct strike finishing in mid air.